Color photography



Patented Nov. 28, 1944 n COLOR PHOTOGRAPHY clayton F. A. white, stelton, N.' J., assigns; by f mesne assignments, to E. I. du Pont de Nemours & Company; Wilmington, Del., a corporation of Delaware Application August k1, 1940, Serial No. 349,310,v

21 Claims. (Cl. 958) This invention relates to new photographic elements and more particularly to new photographic stripping elements. Still more particularly, it relates to new photographic stripping elements for color photography. The invention also relates to methods of releasably attaching light sensitive layers and/or dye intermediates or color former layers with a support and to processes of color photography.

An object oi" this invention is to provide new and novel photographic stripping lms. A further object is to provide a strippingfilm in which a dye image can be stripped'from a silver or silver salt layer. Another object is to provide a stripping lm containing separate dye .intermediate or color former layers and light sensitive layers. A further object is to provide a photographic nlm wherein a color scene or component color aspects may be faithfully recorded. Another object is to provide a new and improved stripping lm for multicolor photography.

Still other objects Will appear hereinafter.

In many photographic arts, particularly in photo-mechanical,v graphic and color photographic arts, it is desirable to transfer emulsion layers from the support on which they were originally amxed to another or permanent support. These lms are commonly known as stripping iilms, inasmuch as the original light sensitive layer is releasably connected with the support or base which is usually composed of paper, or a cellulose derivative or synthetic resin or polymeric compound. The sensitive emulsions of such iilms are coated on a thin menstruum or layer of collodion which in turn has been coated 2, v onto an adhesive layer which is carried by a suitor-forming layers and light sensitive silver salt layers. The dye intermediate or color formerlayer or layers comprise an immobile dye intermediate or color former capable of forming a The immobile dye intermediate or color former layer or layers and co-acting separate light sensitive or reducible silver salt layer constitute a color yielding unit. Upon color forming devel- Y opment a dye image is formed in the dye intermediate layer and a,si1ver image in the sensitive layer which can be rmoved. 'I'he dye interme- .diate layer or layers may be directly imposed on the light sensitive nsilver salt layer or a water permeable colloid layer may be placed between such layers. A stripping layer or stratum 'may be placed between the co-acting dye intermediate or color former layers and co-acting layer or between color yielding units and the base or both. rQlhus, after color forming development, it is possible to remove the dye image layer from the rest ofthe iilm.

A plurality of such units may be releasably attached to each other and to a single temporary support in elements which are useful in multicolor photography. In which cases the units can be designated as color yielding component units. The dye intermediate or color former layer or layers of one or more of such units can be stripped from the silver salt layer of the respective u nit which in scme instances is advantageous in that the silver and; silver salt residues do not have to be removed from the colored image.

The separate immobile dye intermediate or color former layers may be of two general types: (1) composed of an immobile'dye intermediate or color former uniformly distributed or dispersed in a water permeable binding or supporting agent, (2) composed of film forming material containing within its structure, dye forming nuclei, i. e., nuclei capable of forming an indophenal, indoaniline or azomethine dye on color forming development and an azo dye on appropriate treatment. In this embodiment the color former itself constitutes a layer or stratum of the film.

The film elements before exposure or processing comprise atb'ase and at least two co-acting contiguous layers, one of which comprises a colloidal binding agent, a light sensitive silver salt and usually a sensitizing dye and the other of which comprises an immobile dye intermediate or color former and are so constructed that a stratum. or strata. are water soluble or swellable so that the dye intermediate or color former layer after development can be removed from the base alone or together with its coacting silver salt layer or subsequent to the removal of the 'color yielding unit from the base.

It will be readily apparent to those skilled in the art from the general considerations' above, that the invention is oi considerable magnitude and is not limited-to one or two specic types of photographicv elements. In all instances, however, the immobile dye intermediates or color formers are maintained in a separate layer from the co-acting light sensitive silver salt layers,-

generally silver halide gelatin layers, but do not have any water impermeable layers or meinbranes therebetween.

The invention will be brieily exempliiedby the following description of the preparation and color processing of a simple 3-layer stripping nlm and l thisl explanation may make the more complex layer. The iilm is exposed to an object eld and then developed with an arylenediamine containing an unsubstituted amino group, whereupon silver images are formed in the light sensitive emulsion layer and dye images in the color former layer. The color layer may then be stripped from the emulsion' layer and base, placed on a temf porary and/or permanent support. A thin transhaving a color corresponding toa different band of the color spectrum.

parent membrane can be attached to the gelatin dye intermediate or color former layer if desired to give more strength prior to stripping.

In an important embodiment of the invention a light sensitive or reducible silverV salt layer is imposed on the base, next a stripping layer and then an immobile dye intermediate or color forming layer. In a modification of this embodiment a thin layer of a water insoluble water-permeable colloid su'cli as cellulose derivatives, e. g., lower alkyl etherA esters, regenerated cellulose, gelatin, agar-agar, etc., may be interposed between the dye intermediate or color former layer and the respective co-acting reducible silver salt emulsiony layer and the stripping layer may be interposed between the color yielding layer and the colloid layer orl between the latter and the silver salt layer. dye intermediate or color former layer or colloid layer may contain a surface active agent which enables them to be stripped from the remainder of the nlm element.

In stripping films for multicolor photography as previously indicated, the elements comprise a plurality of color yielding component units, that is, a plurality of layers wherein the dye intermediates or color Iormers cooperate with the contiguous co-actlng light, sensitive layers; and at least one stripping layer. In general, for direct positive color 4images obtained by reversal methods, the dye intermediates or color formers should form a dye upon development which is complementary in color to the utilized sensitivity of the respective silver salt layer. which is generally initially a silver halide emulsion layer.

Fonmulticolor photography, as described above, the elements comprise a plurality of strippable color yielding component units, that is, a plurality of layers wherein the color formers cooperate with the co-acting light sensitive layers. units embodied in a single element which may be a monoor multi-pack are so arranged and/or sensitized that each unit will produce a dye image In a further modication the l An important aspect of the invention is concerned with elements having a single color unit thereon strippable in whole or in part from. the

base. In such single color elements stripping membranes may be used to give the layers greater mechanical strength. If both the dye intermediate or color former layer are separable from each other and the base,.the elementmay be so constructed that a selective stripping action occurs. That is, the outer layer can be arranged so that it may be removed from the lower coacting layer before the lower layer becomes removable from the base.

Part of the color processing of the novel lm elements hereof can be completed before stripping the color component units or color yielding layers. Inl some instances a complete dyeimage can be produced before stripping becomes necessary. In-such instances, it becomes unnecessary t'o transfer the stripped layers to a temporary support to complete processing.

A practical two-color strpping element comprises a transparent base having a light sensitiveA or reducible silver salt layeron each side theres of, and a separate dye intermediate or color former layer contiguous with the silver salt layer. The color yielding layers comprise an immobile dye intermediate orcolor former which in some instances forms a dye complementary in color to the utilizedrsensitivityof the respective coacting reducible silver layer. A stripping stratum, layer or membrane is interposed between tire base and the sensitive layers or between the color former layers and light sensitive layers or both and may even form a part of the color former layers. y

A practical 3-color element has two diierentially sensitive reducible silver salt layers with the contiguous dye intermediate or colol former layers separated by the transparent base. A third layer is separated from the nearest silver salt layer by at least two layers. The two layers may be the two respective dye intermediate or lcolor former layers, but in some instances at least one additional layer is provided. `Separate stripping stratum, layers and membranes are provided in the element so that the contiguous dye color separated from the base or adjacent light sensi- Y swellable adhesives which have been used in strip- The" tive layer and cooperating color former layer. Additional water permeable layers or stratalmay separate the reducible silver salt emulsion layers and/or color former layers.

The elements for multicolor photography further contain ltering layers or strata. Thus, filtering dyes or pigments which absorbr certain wave length bands of light may be provided in the elements so that certain spectral bands of light will be absorbed and thus do not pass into inner layers whichV are so disposed as to record different wave lengths. The filtering materials or strata may bef disposed in the color former layers or in intervening layers, which in ythis case are composed of water permeable colloids.

The known types of water-soluble or waterping films may be employed for the novel constructions hereof. Alarge number of materials which are suitable for the stripping or adhesive strata or layers are readily available and may be used in making thenovel stripping elements hereof. Water soluble, or alkali soluble cellulose derivatives e. gamethylcellulose, ethylcellulose, cel- Ywater solub v of aqueous acetic acid lulose acetic acid or cellulose glycollic acid and its le salts, .such as alkali metal, ammonium and amine salts; water soluble starch derivatives, e.lg., starch glycollic acid and its water soluble salts; .water Ior alkali e. g., polyvinyl alcohol, polyvinyl vinyl esters, e. g.,

.i formates,A etc.; alkyd resins, polyamldes, water 'sensitive polymeric amino-'nitrogen containing soluble resins.

3 (2) The-second polymeric molecules are built up wholly by artibodies, insoluble in water and 5% ammonium hy'- droxide, but soluble in aqueous acetic acid of concentrations in the range of about 2 to about 5% the lower portion of this range,

and preferably in etc., may be used. s 'I'he last-mentioned polymeric amino-nitrogen bodies have especially desirable propertiesfor certain purposes in that the layer is not dissolved by the alkaline developer or water Vrinse baths, but .is solubilized by the acids present in and at the concentrations usually obtained inthe acid photographic processing baths such as acid stop` baths. fixing baths, reversal bleach baths, ietc. This is 4oi importance for the reason that such strip lms do not tend to loosen and oat away from the temporary support in developing baths. Suitable specific materials are deacetylated chitln, piperidylmethylzein, dicyclohexylaminoethylmethacrylate, piperidyl-N-ethylmethacrylate and morpholino-'N-ethyl methacrylate. Other materials of this type which may b'e used include the deacetylated chitin which may be prepared according to Rigby U. the acid soluble reaction products ofproteins with carbonyl compounds such as lower aliphatic aldehydes and ketones and amines having less than nine lcarbon atoms in which the aminonitrogen is joined to the aliphatic carbon, for exampla'those disclosed in Meigs U. S. Patent 2,143,023, January 10, 1937; the aminocelluloses soluble in dilute acetic'acid amino-nitrogen removed from the cellulose nucleus by a chain of atoms comprising at least one Vcarbon atom, for' example, those described in Hardy U. S. Patent 2,136,296; cellulose amines which are' soluble in a stoichiometricaly amount containing directly attached tothe cellulosic nucleus from 0.5 to 1.5 amino-nitrogens per glucose unit, these aminonitrogens being attached to nucleus carbon atoms, for' example, those in Haskins U. S. Patent 2,136,299; reaction products of vinyl ketone polymers with amino compounds, for example, those described in Balthis U. S. Patent 2,122,707; the products obtained by treating resins having ketone groups with an excess of ammonia or the equivalent thereof and hydrogenating the resulting mixture catalytically at superatmkospheric pressure and temperature, such as those described in Greenewalt U. S. Patent 2.063,158; polymeric amino alcohol `esters of acrylic andl substituted acrylic acids, for example, those' described in Harmon U. S. Patent 2,138,762, November 29, 1938; and the polymeric amino alcohol methacrylates described in Graves U. S. Patent 2,138,763, etc., 'singly or in combination. These polymeric amino-nitrogen containing substances are insoluble in water and 5% aqueous ammonia lbut soluble in aqueous acetic acid of some concentration within the range 2-5%. Thosel soluble in 2% acetic acidv are preferred. These polymerio-nitrogen containing substances may be divided in several groups as follows:

(l). Those which may be termed cellulose derivatives. I'his includes, although not with strict accuracy, deacetylated chitin and the alkylamino fand amino-alkylcelluloses above-identified.

and containing an panying drawings, in which ficial means. They are not synthesized by nature.

In addition to the resinous polymeric amino alcohol esters of acrylic acid or of its homologs substituted in the alpha position by a hydrocarbon radical,` there may be employed resinous reaction 'products of phenols, aldehydes and ammonia or primary or secondary amines, for example, the reaction product of meta-cresol. formaldehyde and diniethylamine.

(3) .The third group consists of protein derivatives containing sumcient amino-nitrogen to enable them to meet the solubility requirements of the deiinition above given'.

^ 'Ihe invention and the structure of representative. types of stripping elements will be more readunderstood by aconsideration of the accom- Fig. l is a diagrammatical cross-section of a stripping ,film for single color photographs or c olor component records. l

Fig. 2 is a diagrammatical cross-section of a modified stripping filmA for single color photographs or color component records.

Fig. 3 is adiagrammatical cross-sectional' a ystripping paper for single color photographs or color component records. i

Fig. 4 is a diagrammatical cross-sectionof a. modified stripping paper for single color photographs or color component records. l

Fig. 5 is a diagrammatical cross-section of a stripping lm for two-color photographs or color component records Fig. 6 is a diagrammatical cross-section of a 40 modified stripping llm for single color photographs or color component records.

Fig. 7 is a diagrammatical cross-section of a stripping film for. three-color photography or color component reco The invention will be further illustrated but is not intended to be limited by the following examples Example I Referring to Fig. 1, a cellulose acetate film base i is suitably subbed and then coated with a light sensitive silver bromide emulsion to form athin layer 2, next sodium cellulose glycollate to form a thin layer 3, and finally is coated a gelatin dispersion containing as an immobile blue-green color former, 1,5-stearyl-aminonaphthol to form a thin layer I.

A second element is made by substituting for the blue-green'color former of layer 4 an immobile magenta color form rsuch as 4,4"osulfo benzylidine bis m dodecylaminophenylmethyl pyrazolone.`

A third element is made by substituting for the blue-green color former of layer I a= yellow color former'such as diacetoacetaminobenzidide.-

'I'he appropriate three-color separation negatives are printed onto the respective stripping 'illms just described and they are each then developed in a solution of the following composigroup consists in synthetic resv insin the formation `of which ammonia in some i is coated an aqueous solution oi'V The three color formerlayers I which now contain blue-green magenta and yellow dye images, respectively, which color component records are washed and finally transferred in register to a permanent support which maybe a transparent yfilm base or a white and reflective base, such as whereupon a natural color transparency print is obtained.

Example II Referring to Fig. 2, a bellulose acetate film base I is coated with a light sensitive silver bromide emulsion to form a thin layer 2, next is coated an aqueous 'gelatin dispersion comprising 6 parts of gelatin, 1 part of 1,2-oxy naphthoylp-dodecylanilide and M part of sodium stearate or reiiection to form a. thin layer 5.

A similar film was made by substituting for the blue-green color former 1-(m-octadecoyiaminophenyl) -Smethyl--pyrazolone.

A similar film wasc made by substituting for the blue-green color former as a yellow color former, dibenzoylacetzenzidide.

Appropriate 3-color separation negatives are printed onto the respective stripping films prepared and they are each developed in an aqueous solution of the following composition:

p-Amino-N-diethylaniiine -grams-- 2 Sodium carbonate` cc-.. ,25 sodiumsulilte, anhy gram-- 1` Potassium bromide doi Water to liter..- l

The three color former layers 5 which now contain blue-green, magenta and yellow positive dye images are washed and ilnally transferred 'to a permanent support as in Example I, whereupon a natural color transparency or reflective prin is obtained as the case may be. A

Example Ill As shown in Fig. 3 a support of double weight photographic paper having a; glossy barytes coating B is coated with. a solution -of deacetylated chitin consisting of Grams Deacetylated chitin 4.00 Lactic acid 4.75 Ethyl alcohol (35%+water 65%) 91.25 l

to form a. stripping layer 1. Over this is coated a thin nitrocellulose layer 8 which is subbed by .coating it with a solution of Grams Gelatin Acetic acid, glacial 3.0 Ethyl alcohol 96.0

to form a layer. A light sensitive silver halidegelatin emulsionwhich preferably contains optical or gelatin sensitizers is coated onto the sublayer, to form a thin layer i0. Onto layer i0 is coated a gelatin dispersion of the immobile color former as'set forth in Example I, to form a color yielding layer il.

' The film element is exposed and then developed in a color forming developer of the type set forth -in yExample I. The lm is then treated in a potassium bichromate bleach bath containing sulfuric acid and then ilxedv inan acid hardening iixing bath. The color yielding unit and the temporary base may be stripped fromv the paper base in the acid bleach bath. If the stripping action of the layer is not very rapid'it may be removed in the fixing bath. After bleaching and i assen Example IV as shown'in Fig. 4 may be made \by coating a paper base 8 with a layer i2 of polyvinyl alcohol, next 'a cellulose nitrate layer I8, ihenooated with a subblng layer u or cellulose nitrate, and ,then coated-with a gelatin silver bromide-iodide emulsion layer IB and finally a gelatin dispersion of the immobile color former 1,2-oxynaphthoyl-p-dodecylanilide, to form a layer I6. The element may be processed after the manners set forth in Examples I, II or III. Stripping may be accomplished after first development. v

- A similar film may be prepared by interposing a clear gelatin layer between layers I5 and Il. Similar elements may be prepared by substituting a iilm forming dye intermediate color former for lthe gelatin dispersed dye intermediates or color formers of the elements described in this example.

A stripping nlm Example V Three stripping films werey made after the manner set forth in Example. I bysubstituting for the blue-green color former m-octadecyloxyphenol, for the magenta color-former, v4,4'bis (3"-methylpyrazolonyl-l") biphenyloxide for the yellow color former acetoacetaminophenylmorpholine, and for the strippinglayer thereof, .a layer applied from a solution of deacetylated chitin consisting of Parts peacetylated chitin 4.00 Lactic acid 4.75 Ethyl alcohol 91.25

permanent support which may be transparent or.

white and reflective.

Example VI Referring to Fig. 5, .e dupliooetea Stool: provided with two removable color yielding component layers is prepared by coating -a film base I on each v side with a ypositive type gelatino silver bromide emulsion containing 4 grams of tartrazine per kg. of emulsion to form thin layers 2 and 2'; upon these layers are coated a polyvinyl alcohol water solution to form thin layers 3 and 3'. A gelatin dispersion of the yellow color former diacetoacettolidine sulfone is coated on layer 3 to form a thin layer 4. 0n layer 3 is coated a gelatin dispersion of the magenta color former 1-(m-stearoylaminophenyl) -3-methyl-5-pyrazolone to form a thin layer 4'.

The element just described may be printed from the blue and green negative color composition records of a tri-pack combination and processed to color images as in the previous example. The yellow and magenta color image elements thusA produced can be combined with a blue-green color element produced on a separate stripping element to form a complete color photograph.

Example VII A nlm element of the type set forth in Example VI is prepared by substituting for the color former of layer 3 a mixture oi' the yellow color former prepared by condensing o-sulfobenzaldehyde with diacetoacet-tolidine suli'one and a magenta color` former such as 1-(m-stearoylaminophenyl-3- methyl--pyrazolone, and for the color former ot layer I', 1,2-oxynaphthoy1-p-laurylanilide.

l This element may be used for printing bipack i negatives (2-color) and will serve for the complete record. The front-negative iilm of the bipack is printed onto layer 3 and the rear negative llm printed onto layer 3. i The nlm is then developed in a bath of the following composition:

2-amlno-5-diethylamino toluene hydrochloride -grams 4 Sodium suliite, anhydrous. do l 2 `Water to liter" i The layers l and Il' which now contain orange- `red and blue-green dye images, respectively, are

be used. rli'hese may be firmly pressed onto theV color layers. Other suitable materials are syn l thetic resins, e. g. polyvinyl esters such as polymerized vinyl acetate; polyvinyl acetals which are the condensation products of partially or completely hydrolyzed polyvinyl acetate and an aldehyde such as formaldehyde, acetaldehyde or butyraldehyde, alkyd resins, i. e., condensation products of polybasic acid compounds and poly- Vhydroxy alcohols, e. g., from phthalic, adipic,

succinic, maleic, fumarie, etc., acids and anhydrides with glycerol, ethylene glycol, diethylene glycol, pentaerythritol, sorbitol, etc.; nylon, i. e., nlm forming amide polymers (see U. S. Patents 2,071,250, 2,071,253, 2,130,948, and 2,141,169), etc.

The use or thin membranes is desirable when a color-former which is composed of a lm forming material containing within its structure dye forming nuclei because such lms need additional support or strength when they are stripped from other layers. Such iilms are of considerable utility and have definite advantages since proc esslng need not be carried beyond color development and washing. The color images are removed aiterrst development and the remainder of the nlm may be discarded if desired without bleaching and fixing.

`Example VIII I A film element as shown in Fig. 6 is prepared by coating ak cellulose nitrate film base I with a gelatin subbing layer 1, next with a-stripping layer 3 comprising:

Piperidylmethylzein Acetic acid Ethyl alcohol nextf'a thin film of nitrocellulose obtainedu by f color record yfrom the particular color 5 This thin, water-permeable nitrocellulose film is then provided with a substratum coating I1 ob tained by coating the nitrocellulose nlm with a solution oi' Grams Gelatin 1.0 Acetic acid, glacial 3.04 Ethyl alcohol 96.0

llxing bath. a suitable formula for which is as follows: f

Hypo, crystals grams `240 "'Sodium suliite, anhydrous do 15 Acetic acid, glacial do l5 Boric acid do 5 Potassium alum do 8 Water to liter-- 1 While the lm is ln the fixing bath, the piperldylmethylzein is solubilized by the acetic acid of the bath and the emulsion layer with its thin lm support can be stripped from the 'temporary or 'original support and support whereupon it can be bleached, color developed and the silver and silver salts removed, then transferred to the iinal support.

Various types of immobile dye intermediates or color formers may be substituted with similar results. The resulting films are extremely useful when the proper color formers are chosen in the preparation of natural-color prints. In general, each stripping iilm should contain the dye intermediate color former to reproduce the proper separation negative employed for printing.`

A multilayer lm element as shown in Fig. 7 is made by successively coating a subbed cellulose nitrate illm base I, a stripping membrane 20 composed oi' nitrocellulose, next with a red sensitive silver bromide emulsion layer 2|, next a gelatin layer 22 'containing as an immobile blue-green color-former the octadecyl ether of resorcinol, next is coatedan acid stripping layer 23 from a solution containing:

Grams Piperidylmethylzein 4.0

hrome alum 0.2 Suliamic acid 4.8 Ethyl alcohol (65% water) 91.0

A thin film 24 of Water-insoluble water permeable ethylcellulose is coated from a solution of:

On layer 24 is coated a green sensitive gelatino silver bromide emulsion layer 25, then a gelatin layer 26 containing an immobile color former such as i-(m-stearoylaminophenyl)-3-methyltransferred to the second -pyrazolone, over which is coated an alkali stripping layer v2l from a solution of Parts Gelatin 2.0 vDextrin 2.0

Water Next is coated a thin membrane 28 of a waterinsoluble water-permeable ethyl cellulose from a solution of asesinas structures with stripping layers and/or mem- Grams Ethylc'elluiose --.1., 5.0 Methyl acetate 77.0 Acetone 11.7 Xylene 6.3

Then a blue sensitive gelatino silver bromide emulsion containing a removable yellow illter dye such as tartrazine to form a layer 29, and finally a gelatin layer 30 containing a yellow color former such as `benzoylacetamino phenylmorpholine.-

After exposure to a colored object or scene this multilayer strippingillm is developed in a nonhardening alkaline developer; At the completion of development unit A is stripped oil`v and transferred to another support whereupon the silver image can be bleached in an ordinary sulfuric acid-potassium dichromate reversal bleach bath. However, for purer color, a sulfamic acid-potasp-Aminodiethylaniline -grams-- 8 Sodium carbonate, anhydrous ..d 40 Sodium sulflte, anhydrous do.. 5 Water fo liter-- 1 to yield an insoluble yellow -azomethine dye in situ with the silver image. After washing the film, the silver image is removed by'means of the ordinary Farmer's reducer and the yellow image transparency is given the final wash.

At the completion of fixation, film unit B is stripped olf, transferred to a temporary support, washed, bleached, re-exposed and redevelcped in the p-amino-N-dialkylaniline developer as described above and the silver image removed in the manner described. Film unit C, xed to the original support, is washed, reversed. re-exposed, re-developed and the silver removed as indicated above, thus revealing the glue-green dye image. Then the magenta dye image bearing lm unit 1B is transferred from its temporary support and squeezed into register on the bluegreenimage layer and the same operation is carried out with the yellow image fllmunit A. Thus, a multicolor, positive transparency is pro- -duced by the use of this selectively delayed stripping fllm, one of the stripping layers of which comprises a polymeric amino-nitrogen containing body, insoluble in water and 5% ammonium hydroxide but soluble in 2% acetic acid.

The invention is not limited to the particular arrangement of layers set forth in the preceding example. On the contrary, various types of three color films may be prepared by placing the color former layers in dierent manners. Thus, the types of 3-color film elements disclosed in application Serial No. 349,228,l rlled August 1, 1940, may be used by further modifying such agent (2) soluble in aqueous branes between respective units of light-sensitive layers and the co-acting color former layers. Thus, two-color former unit layers may be placed on one side of the support and one unit on the other.

may, for example, constitute the middle unit of a 3-color element having three units on one side of a single support, .and appropriate stripping l layers interposed so that the respective units may be similarly processed.

In the embodiment of the invention wherein no re-exposure to light is used, the dye forming solutions set. forth in Meschter application, Serial No. 259,686 now U. S. P. 2,310,981, may be used with excellent results.

In place of the specific immobile color formera set forth in the preceding examples may be substituted a large number of .exceedingly diverse dye intermediates or color formera, capable of forming indophenol, indoaniline or azomethine dyes. The types which are to be dispersed in gelatin or`other similar colloid binding agents may be (l) substantive to the gelatin or binding alkaline liquids but fast to diffusion when present in emulsion layers, (3) colloidal in nature so that they cannot be removed by simple extraction from the layer, (4) of high molecular weight so that migration through the cellular structure of the binding agent is prevented, (5) highly insoluble. (6) nlm forming. Substantivity can be strengthened by agents which have precipitating action,

e. g., dipheny1 guamdme, dipnenyibiguanidme,

etc.

I'he immobile dye intermediates or color formers in general contain two components, (1) a color forming dye coupling component or nucleus and va component group or nucleus which increases the molecular weight so that they become immobile in water permeable colloid layers, or (2) groups for imparting substantive character (which may be of the same type as used in making dyestuffs substantive to cotton), or (3) groups or structures which make it colloidal in character.

Suitable dyestuif components for color-forming development and azo reversal processes hereo'f which fall within one or more of the abovev types of immobile color formers include: l

1. Higher aliphatic and cycloaliphatic derivatives of dye intermediates wherein the aliphatic radical such as an alkyl, alkoxy or'long chain carboxylic acid acyl radical contains a carbon chain of more than 8 carbon atoms and preferably at least 12 carbon atoms, such compounds including active methylene compounds such as aroylor acylacetanilides, phenylmethylpyrazolones', etc., higher aliphatic amides of phenolic compounds, and alpha-andv beta-naphthols which preferably contain' some -solubilizing group such as carboxyl or sulfonic, which are characterized in that they have v reactive posi- )tion capable of entering the coup ing reactants but not necessarily an unoccupied position ortho or para to the phenolic hydroxyl group. Suitable compounds ofthe cycloaliphatlc'type are set` forth in U. S. Patent 2,189,817.

2. Polyvinyl acetals of aromatic aldehydes which are capable of reacting with diazo compounds and the oxidation productsv of photographic color developers. Theacetals are formed from polyvinyl alcohol orpartially hydrolyzed polyvlxkvl esters and aromatic alde- A green blind red sensitive silver halide layer assures.'4v 1- V j m '7] `f position, ortho or parato the mentioned groups or the aromatic aldehydes having an active ,methylene group.v The preparation of suitable compounds of this type is set forth in Dorougli 8; McQueen application, Serial No. 233,480, iiled October 5, 1938now" Il. S. P. 2,310,943.

` `3. ACondensation products of phenols and naph- `thols or hydroxy aromatic carboxylic or sulfonic acids with difunction'al, resin forming reagents hydrochlorid organic acid salts may be used inthe preparation of the developing solutions. The salts are in general more stable than the free bases. As examples oi' suitable salts. mention is made of the sulfates, acetates, etc.

Further examples of developing agents that can be used in this process are-heterocyclic compounds containing benzene nuclei such as 1,2,3,4` tetrahydro-B-aminoquinoline, 1,2,3.4tetrahydro (British Patent 47B,- 345); o-aminophenols and their substitution products (French Patent 806,649); N-hydroxyalkyl p-phenylenediamine (British Patent 460,- 580); halogenated p-aminophenols (French Patweight compound such asfaliphatic acids or such as aldehydes and ketones. dimethylol derivl5 ent 813,902); p-phenylenediamine derivatives atives of phenols,` amides and amines and equivcontaining solubilizing groups in the positive radalent compounds. 'I'he preparation of suitable color :formers of this type is described in McQueen 822,269) application, Serial No. 261,794, tiled March 14,

. 1939, now U. S. P. 2,323,431. 20 v 4. Condensation products of amine-containing dyeintermediates such as aminophenols, amino- 'I'he stripping illms hereof are not limited to color forming development processes.. On the contrary, azo reversal processes as set forth in naphthols, N-ztminoalkyll or aminoaryl-aminoaforesaid application Serial No. 349,223, may be naphthols, amine containing active methylene used with successful results. ,Suitable diazo socompounds such as amino aroylor acetyl-acet- 25 lutions for preparing remote images in the color anilids, amino-phenylmethylpyrazolones or any of former layers only may be prepared from many thepreceding compounds containing solubilizing primary lamines and aromatic amines which are `groups such as carbonyl or sulfonic, with polyear`A l suitable for diazotizing and coupling to azo dyes boxylic acids and their derivatives such as the are well known in the art (see Fiera-Davis anhydrides, esters. amides or halides. merio acids include the olefin-maleic anhydride interpolymers, polyacrylc acids and interpolymers of esters of olen dicarboxylic acids with f vinyl esters, oleiins and styrene as described in Cain The Chemistry of the Diazo Compounds," pages 6-26) They are in general of the type RNI-I: where R. is aromatic or a heterocyclic ring such as pyridine, .pyrazolona etc. The R may Such polyao Kunstliche Organische Farbstaile and J. C.-

U. S. Patent 1,945,307. also be substituted with various groups such as- 5. Immobile dye intermediates formed from N- mono and dialkylated or aralkylated 1,5- and 1,8- aminonaphthols containing in -a side chain a group capable of further condensation such as amino, thio, carboxyl, formyl, etc., by condensing said compound with a suitable high molecular halogen, alkyl, alkoxy, aryl, sulfonic, carboxyl, etc. Inchoosing the amine to be used there are in general two considerations to be observed, (1) the diazo compound must be sufficiently active to couple readily with the dye intermediate used at a relatively low temperature and in aqueous solution; (2)v the diazo compound must be one amines with more than 8 carbon atoms or polywhich can be coupled to yield bright azo dyes with meric materials such as polyvinyl alcohol or polyspectral characteristics suitable for use in threemerio acids or derivatives as listedabove in paracolor photography. that is, they must have fairly graph 4. 4

Suitable immobile dye intermediates of the above and other types which are useful for color development and azo-coupling processes are disclosed in U. S. Patents 2,154,918, 2,166,181, 2,l78,` 612, 2,179,228, 2,179,238, 2,179,239, 2,179,244, 2,186,045, 2,186,719, 2,186,734, 2,186,735, 2,186,736, 2,186,849, 2,140,540, 2,183,937, 2,200,924, etc., and may be substituted for the dye intermediates oi the above examples in' ,accordance with the teachings hereof.

definite and sharp absorption bands. Thus. the most suitable amines are those containing halogen. alkoxy, nitro, carboxy. and sulfonic acid groups. l

For successful operation of the azo reversal processes hereof, it is necessary to have diazonium compounds that will couple with three colorless components to yield the three suibtractive primary colors, yellow, magenta and blue- Almost all diazotizable amines can be coupled with phenolic coupling components and p diamines of 1 to 4 carbon atoms, e. g., p-aminodi`- ylenediainine, etc. These aromatic amino-devel- The preferred developingagents which may be active methylene compounds such as phenyl-` used in the dye coupling developmentsteps here- Y methyl pyrazolone, acetoacetanilide and aroylf of are derivatives of p-phenylenediamine and acetanilides, etc., to yield greenish-yellow to particularly the asymmetric dialkyl p-phenyleneso orange-yellow azo dyes. The number of combinations that yield magenta dyes is somewhat methylaniline, p-aminodiethylaniline, pamino-\ limited. since the coupling component 'to condibutylaniline, etc. Other developing agents Qionn to the previously mentioned requirement which may be used include p-phenylenediamine must be substituted alpha naphthols, and only a itself, p-methylaminoaniline, p-ethylaminoaninumber "oi' diazonium compounds will line, p-aminophenol, N,N.diethylophenylenedi ense with such components to form magenta amine, chlororp-phenylenediamine, 1,2,5-toluylcolors. Ihua diazotlzed aniline derivatives yield enediamine, 2-aminof-diethylamino-toluene, pa magentehcolor only when substituted `in the amino-N-pheriylmorpholine, .N-p-aminophenyl- .piperidina 4N--methyl-N-hydroxyethyl-pfplfienyl- 7o and nitro. t

diamine., N-butyl-Nfhydroxyethyl-pephenylediamine, 2-amin'o-/5-(N-butyl-N-hydroxyethaminotoluene, uw#dihydroXipropyl-p-phen- Tetaazotized diamine compounds such as` benzidine and diaminonaphthalene derivatives substituted with halogen, alkoxy, and v sulionic acid groups may also be used. In iormins the blue-green azo color. the choice is furortho or para position with such groups as phenyl oping agents in the forml of their organic or in- 76 ,ther restricted since the best colorless coupling i A secondary components which adhere tothe previous qualifications are derivatives of 1.5 and 1,8-aminonaphthol in which the amino group is preferably or tertiary, and must remain basic. The preferred diazotizable amines that can be used for forming all three colors therefore are substituted benzidine derivatives containing halogen, alkyl, nitro, carboxyl, alkoxy or sulfonic acid groups, and derivatives containing the 2 position halogen, alkoxy, nitro, carboxyl or sulfonic acid groups which all give desirable properties to the diazo components and to the dyes. y

t While gelatin has been described as the bindw-` ing or supporting agent in the majority of the examples, the invention of this material. On thecontrary, a large number of materials some of which are readily available can fbe substituted in similar amounts and coated in the above manners. Natural and synthetic materials such as gums, resins, cellulose derivatives, carbohydrate derivatives', etc. The materials in general must be substantially cold water insoluble but water permeable.

Suitable speciilc materials include ,poly-vinyly alcohols including partially hydrolyzed polyvinyl I esters, e. g., polyvinyl chloride and polyvinyl acetate; modified with resins such as polyvinyl acetals so that they have the above recited properties. The acetals maybe formed from acetaldehyde, prospionaldehyde, isolbutyraldelrvde, benzaldehyde, etc., ketones, glyoxylic acid, etc., alkyd resins including the modied alkyd resins which are prepared from Polyhydric alcohols, e. g., glycerol, ethylene glycol and higher glycols and ptoybasic acids, e. g., phthalic, maleic, succinic, e y

lCondensation products of phenols, of naph- -thols, or `of hydroxy aromatic carboxylic or sulfonic acids with bifunctional resin-forming reagents, for example, aldehydes and ketones, dimethylol derivatives of phenols, of amides, or of amines, and of equivalent compounds may be used.

Condensation )products of amine-containing dye intermediates, with lpolycarboxylic acids or with their derivatives such as the anhydrides, esters, halides, or amides may be used. Polymeric acids of this type and their derivatives include the polyvinyl ethers of hydroxy acids, olen-maleic anhydride interpolymers, polyacrylic acid, polymeric olefin dicarboxylic esters and interpolymers of esters of olefin dicarboxylic acids with vinyl esters and U. S. Patent 1,945,307.

The above and equivalent materials as previously indicated can be used as binding agents for the color yielding layers as well as the silver salt layers or intervening-,layers in each of the herein described constructions of film elements.

While cellulose derivatives have been described in the majority of the examples, various other types of transparent, translucent as well as opaque supports may be used. Synthetic resins including acrylic and hydrocarbon substituted acrylicy acid resins, meta-styrene resins, vinyl resins, e. g., vinyl chloride acetal, polyvinyl-acetals, synthetic linear polyamides, glass, paper and many other materials may be used.

Various types of reducible silver salts may be used in the light sensitive layers.` Initially they are generally silver halide layers such as simple and mixed chloride, bromide, and iodide emulsions, including silver bromide, silver chloride, silver chloride-bromide, silver bromide-iodide,

substituted para-nitro-aniline is not limited to the use styrene as described in.

.canbemadeupand silver iodide, etc., or the type used in the more conventionalfllm elements used for color forming development. They may contain ,the'usual emulsion components s uch as stabilizers, antifogging agents, sensitizing dyes, e. g., cyanine, carbocyanine, azine, carbocyazine. pinaflavol, etc., salts and bases; etc. These light sensitive emulsions after development to silver images may be bleached in the usual manner to form silver ferrocyanide images before color development or color formation.

The particular types 4of 'coating solutions used coated in a manner similar to those which have been used in the manufacture of film elements containing immobile dye intermediates in emulsion layers. The immobile dye intermediates may be dispersed in the binding agents while in a ilnely divided state using dispersing agents if'desired and/or alkalies. In many cases it is practical to dissolve the dye intermediate or color former in a 5 to 10% caustic alkali to form a soluble paste. This may be then diluted with about 5 parts of water and about l part of alcohol added to 5% aqueous gelatin and the excess jalkali neutralized with a mineral acid such as hydrochloric. The usual photographic -coating ingredients. spreading agents, e. g., glycerine, salponine, long chain alkyl sulfates, etc.,

'may be employed. The concentration of the coatt yield the desired thickbing solutions may also be employed to anchor' the dye intermediate or color former layers to adjacent layers which may be emulsion ,layers or intervening layers.'

The stripping lms hereof have a number of decided advantages. In the forms wherein the color former layers are strippable from the light sensitive layers an important economic advantage is attained in that the light sensitive layers may be discarded after initial color forming development,'since they require no further processing. A related advantage is the fact that thinner final multicolored elements are produced which have excellent projection properties.

A further feature that the sensitivity of the silver halide emulsion layers is not impaired. yMany color formerswhich are readily available and form excellent qulnoneimine, aaomethine and am dyes have a very deleterious effect on the speed of photographic emulsions and for this reason cannot be, used in -prior art-elements. In many cases the contrast and sensitivity of the nlm is excessively depressed, by their incorporation in emulsion layers.

Another important advantage resides in the improved stability of the resulting film elements. 'I'he methods employed for incorporating color formera in. emulsions often lead to unstable films. overcome by this invention. Furthermore, some color formers fog the sensitive emulsion whenincorporated therein. This decided disadvantage is overcome by the present invention.

A further advantage resides in the fact that a wider selection `of optical sensitizers is permitted. In a multiple color element".film, lsolatingmedia segregate each element in such pseudocyanine, merocyanine, cy-

important advantage resides in the- The aforementioned disadvantages are fashion that dye image formation is dependent only on processing steps within the photographic layer associated with each respective element The invention also provides the following production advantages. y i

(a) Color former dispersions may be prepared in advance of the coating schedule. They may be standardized for degree of dispersion, colloidal stability, and color forming strength. All these operations may be carried out in white light areas; darkroom conditions being unnecessary prior tothe coating operation. l

(b) 'I'he consumption of costly materials is reduced since the colloidal dispersions are relatively stable, thus permitting them to be reworked by re-melting the chilled and jelled dye# forming colloid. 0n the other hand, previous research has shown that the photographic stability of light sensitive emulsion-color former preparations is short-lived and the uncoated preparations deteriorate rapidly even under refrigerated storage conditions.

As many apparently widely diil'erent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to fbe understood that I do not limit myself to the specific embodiments herein except as defined by the appended claims. I claim:

1. A stripping photographic element comprising a base. having superposed thereon at least two coacting layers, one of which is light sensitive and the other of which is light insensitive and cold-water insoluble and comprises an immobile dye intermediate capable of formingboth an azo l dye and a dye selected from the group consisting -of indophenol, indoaniline and azomethine dyes and a stripping layer comprising an adhesive stratum composed of an adhesive taken from the group consisting of water-soluble and waterswellable adhesives and of different composition and solubility characteristics from the aforesaid two coacting layers and which is disposed in the element in such a manner that at least one of aforesaid coacting layers is removable from the base by a stripping process; each of said layers being permeable to aqueous developer solutions.

2. A photographic element comprising a support, at least one color yielding unit releasably attached to said support by means of a watersoluble adhesive, said unit comprising a lightsensitive silver halide layer and at least one co- 9 kenne muxas but :est to diffusion in said co1- loid and capable of forming both an azo dye and a dye selected from the group consisting of indophenol, indoaniline and azomethine dyes, and a Stripping layer comprising an adhesivestratum composed of an adhesive taken from the group consisting of water-soluble and water-swellable adhesives and of different composition and soluacting, light-insensitive, water-permeable,f separate layer comprising an immobile dye intermediate capable of forming both an azo dye and a dye taken from the group consstlng of lndo phenol, indoaniline and azomethine dyes, said adhesive being of different composition and solubility characteristics from the aforesaid two coacting layers.

3. An element as set forth in claim 2 wherein the silver halide layer is outermost.

4. An element as set forth in claim 2 wherein the silver halide layer is adjacent the support.

5. An element as set forth in claim 2 wherein said support is paper.

. i 6. An element as set forth in claim 2 wherein said support is a transparent film base.

, p 7. A stripping photographic film comprising a4 supporthaving superposed thereon at least one light-sensitive silver halide layer and at least one separate coacting light-insensitive layer comprising a cold-water insoluble, water-permeable colloid binding agent containing an immobile dye intermediate which -is soluble in aqueous al- :bility characteristics from the aforesaid two coacting layers and which is disposed in the element in such a manner that atleast one of aforesaid coacting layers may be detached in aqueous photographic processing solutions by a stripping process. A v

, 8. An element as set forth in claim '7- wherein the silver halide layer is outermost.

9. An element as set forth in claim '.7 wherein the silver halide is adjacent the support.

10. An element as set forth in claim '7 wherein said support is paper. Y

11. An element as set forth in claim' 7 wherein said support is a transparent film base. l

12. A stripping photographic illm comprising .a support having superposed thereon at least one light-sensitive silver halide emulsion layer and a separate coacting, light-insensitive layer comprlsing an immobile dye intermediate in the form of a water-permeable, cold-water insoluble film containing within its structure a dye forming nuclei capable of forming an azo dye and a dye taken from the class consisting of indophenol, indoaniline and azomethine dyes, and a stripping layer comprising an adhesive stratum composed of' an adhesive taken from the group consisting of water-soluble and water-swellable adhesives and of different composition and solubility characteristics from the aforesaid two coacting layers, whereby at least one of `said coacting layers may be removed from the base by a stripping process. l

13. An element as set forth in claim 12 wherein the silver halide layer is outermost.

14. An element as set forth in claim 12 wherein the silver halide layer is adjacent thesupport.

15. An element as set forth in claimlZ wherein said support is paper.

16. An element as set forth in claim 12 wherein said support is a transparent film base.

17. A photographic stripping film comprising a support, at least one color yielding unit releasably attached 'to said support by means of a stratum of a water-soluble adhesive, said unit comprising in order alight sensitive silver halide layer, an intermediate, light insensitive, water permeable colloid layer and at least one coacting, light insensitive, separate layer comprising an immobile dye intermediate capable of forming an azo dye and a dye taken from the group consisting of indophenol, indoaniline and azomethine dyes, said unit being permeable to aqueous color coupling developer solutions.

18. An element as set forth in claim 17 wherein the silver halide layer is outermost.

light insensitive, color yielding layer which comprises an immobile dye intermediate capable'of forming` both an azo dye and a dye selected from the group consisting of indophenol, indoaniline and azomethine dyes, said layers, stratum and membrane being permeable to aqueous colorcoupling developing solutions.

21. A stripping photographic nlm comprisingv .a support having superposed thereon at least one light-sensitive silver halide layer and at least one coacting light-insensitive water-insoluble layer comprising: a water-permeable colloid binding agent containing an immobile color former, at least one of said 'layers having atasosnce Y 

